Pressure detecting device for vehicle

Abstract

In a pressure detecting device for a vehicle, a first detection member is fixed to a sensor housing such that a first surface of a first diaphragm faces a closed space of the vehicle and a first chamber isolated from the closed space is provided to face a second surface of the first diaphragm. A second detection member is fixed to the sensor housing such that a first surface of a second diaphragm faces the closed space, and a second chamber is provided to face a second surface of the second diaphragm. When the first diaphragm and the second diaphragm are deformed by the same amount and in the same direction, the first detection member and the second detection member output signals having the same value with opposite signs. The first surface of the first diaphragm and the first surface of the second diaphragm are covered with a protection member.

What is claimed is: 
     
       1. A pressure detecting device comprising:
 a sensor housing; 
 a first detection member including a first diaphragm, the first detection member being fixed to the sensor housing such that a first surface of the first diaphragm faces a closed space and a first chamber being isolated from the closed space is provided to face a second surface of the first diaphragm, the first detection member outputting a signal when the first diaphragm is deformed according to a pressure in the closed space; 
 a second detection member including a second diaphragm, the second detection member being fixed to the sensor housing such that a first surface of the second diaphragm faces the closed space and a second chamber is provided to face a second surface of the second diaphragm, the second detection member outputting a signal having an absolute value the same as an absolute value of the signal outputted from the first detection member but having an opposite positive or negative sign from that of the signal outputted from the first detection member, when the second diaphragm is deformed by a same amount and in a same direction as the first diaphragm; and 
 at least one protection member being filled in the sensor housing and covering the first surface of the first diaphragm and the first surface of the second diaphragm. 
 
     
     
       2. The pressure detecting device according to  claim 1 , wherein
 the first detection member and the second detection member are arranged in a direction parallel to a planar direction of the first diaphragm and the second diaphragm. 
 
     
     
       3. The pressure detecting device according to  claim 1 , wherein
 the second chamber is in communication with the closed space. 
 
     
     
       4. The pressure detecting device according to  claim 3 , wherein
 the second chamber is provided between the second surface of the second diaphragm and the sensor housing, and 
 the sensor housing is formed with a housing communication hole that allows communication between the second chamber and the closed space. 
 
     
     
       5. The pressure detecting device according to  claim 1 , wherein
 the first chamber and the second chamber are in communication with each other, and are integral with each other. 
 
     
     
       6. The pressure detecting device according to  claim 1 , further comprising:
 a calculation circuit that adds a detection value of the first detection member and a second detection value of the second detection member. 
 
     
     
       7. The pressure detecting device according to  claim 1 , wherein
 the closed space is provided inside of a door of a vehicle, and 
 an increase in the pressure in the closed space is detected according to a compression of the closed space in an event of a collision to the door. 
 
     
     
       8. A pressure detecting device comprising:
 a sensor housing; 
 a first detection member including a first diaphragm, the first detection member being fixed to the sensor housing such that a first surface of the first diaphragm faces a first direction and a first chamber is provided to face a second surface of the first diaphragm, the first detection member outputting a signal when the first diaphragm is deformed; 
 a second detection member including a second diaphragm, the second detection member being fixed to the sensor housing such that a first surface of the second diaphragm faces a second direction opposite the first direction and a second chamber is provided to face a second surface of the second diaphragm, the second detection member outputting a signal having an absolute value the same as an absolute value of the signal outputted from the first detection member but having an opposite positive or negative sign from that of the signal outputted from the first detection member, when the second diaphragm is deformed by a same amount in a same direction as the first diaphragm; and 
 at least one protection member being filled in the sensor housing and covering the first surface of the first diaphragm and the first surface of the second diaphragm. 
 
     
     
       9. The pressure detecting device according to  claim 8 , wherein
 the first detection member and the second detection member are arranged in a direction parallel to a planar direction of the first diaphragm and the second diaphragm. 
 
     
     
       10. The pressure detecting device according to  claim 8 , wherein
 the first chamber and the second chamber are in communication with each other, and are integral with each other. 
 
     
     
       11. The pressure detecting device according to  claim 8 , further comprising:
 a calculation circuit that adds a detection value of the first detection member and a second detection value of the second detection member.